We want your brains
"SPOILERS" "SPOILERS" "SPOILERS"
OK, lets say I buy the premise of the movie; the aliens need human brains to be put into new aliens and machines.
The ending implies that when the brain is in the new body it carries the human personality and memories with it.
Lets say the aliens (allowing for wastage) get 5 billion brains from Earth.
Haven't they created 5 billion enemies equivalent in strength to themselves?
"Knowledge is cheap at any price"